This issue of The Lancet carries an interesting article on congenital malformations near waste landfill sites. Helen Dolk and colleagues have combined data from several sites in Europe, thus enhancing the statistical power of the analyses and facilitating comparisons between the different sites. Although the results are intriguing, the lack of adequate exposure information makes interpretation difficult. It is not even clear that the study populations are excessively exposed to toxic agents originating from the landfills. Other studies have been done on adverse health effects in populations living near waste landfill sites, notably in the USA, 2, 3 and 4 but no clear picture has emerged.